Optimization Effect of Lorentz Force on Local Perturbation of Flow Field around Submarine

While a submarine navigates underwater, the drag against submarine increases for the reasons such as flow separation and boundary layer transition near the wall, which are resulted from fluid viscosity. Meanwhile, massive vortices appear in the flow field accompanied by abnormal vortex shedding. Based upon the viscous incompressible Navier-Stokes equation, this study employs the finite volume method to numerically simulate the submarine’s flow field with Re=107. The flow field and the force evolution on the submarine are analyzed respectively under the conditions of A=1, A=2, and A=3, where electromagnetic force(Lorentz force) is applied for flow field control. The results show that the vortices on the hull are effectively suppressed when the Lorentz force is applied to the junction of the hemispherical forebody and midbody(A=1, N=1.5). Applying Lorentz force to the top of fin(A=2, N=1.5) can effectively suppress the vortex shedding, and greatly reduce the drag force(horizontal component of force). Therefore, appropriate utilization of Lorentz force for controlling the boundary layer flow of the fin may efficaciously suppress the formation of irregular vortices and their shedding, and reduce flow noises, hence improve the stealth and the dynamic performance of a submarines. This study may provide a reference for optimization of submarine flow field.